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Old 23-03-2007, 11:11 AM
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Geoff45 (Geoff)
PI rules

Geoff45 is offline
 
Join Date: Jul 2006
Location: Sydney
Posts: 2,631
Quote:
Originally Posted by DougAdams View Post
The other alternative is to pop the laser in a barlow and look for the doughnut reflected back up the drawtube. I believe this skirts the problems of having your laser out of collimation. I've been using this method and it seems to work fine - very easy. I had to fashion a cap from an old eyepiece cover to fit over the drawtube inside the OTA (bit like the BLUG).
This is by far the best method. Try rotating your eyepiece tube using the laser without the barlow, and I'll bet your "perfect" collimation changes. With the barlow, things stay stable. Google "barlowed laser" for more info, or look here http://gmpexpress.net/~tomhole/blaser.pdf
Geoff

Last edited by Geoff45; 23-03-2007 at 01:29 PM.
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